I finally got things to work by actually defining USE_ARES in config.h, rather than in the project settings. Now I can run with no problems. I do wonder what happened, though. I didn't see USE_THREAD_GET defined anywhere in the code...

the closest thing I could find was CURLRES_THREADED, defined if you're running W32.

I have code I can give you, but I'm not sure how... I've got a zip file containing the source, but I don't imagine the list mailer includes attachments. I'll try anyway. You'd have to change the include path and lib path for libcurl in the project settings.